Here's what I think the southern part of the trade caravan might want. This is in no particular order:Ummm.... OK, you have lots of things the mediterranean countries might want.
What's going the other direction?
-Probably would want to import different horse breeds.
-Rock salt from the Sahara.
-Wine.
-Date fruits.
-Glassware.
-Incense from the northeast.
-Blank Papyrus.
-Scrolls.
-Importing the art of making mosaics
-Artwork (Paintings, sculpture, northern jewelry, etc)
-Fine Pottery
If there habitat was more expansive than modern day OTL , I would include another Old world monkey Sahelian export: the Drill.
That and the Mandril should fetch great prices up north; Very distinctive appearances and somewhat large.